The number 42 is famously known as the "Answer to the Ultimate Question of Life, the Universe, and Everything" in Douglas Adams' science fiction series, The Hitchhiker's Guide to the Galaxy. In the story, a supercomputer named Deep Thought calculates this answer after seven and a half million years of computation, but the actual question remains unknown. This concept has since become a cultural reference, symbolizing the search for meaning in life. The number 42 is often used humorously in discussions about philosophy, science, and the complexities of existence, highlighting the absurdity of seeking simple answers to profound questions.